package org.abc.utils
{
	import flash.display.BitmapData;
	import flash.display.BlendMode;
	import flash.display.DisplayObject;
	import flash.display.Sprite;
	import flash.geom.ColorTransform;
	import flash.geom.Matrix;
	import flash.geom.Point;
	import flash.geom.Rectangle;

	public class HitTestUtil
	{
		//判断两个任意形状的物体是否有实际象素接触 
		public static function complexHitTestObject(target1:DisplayObject, target2:DisplayObject, accurracy:Number=1):Boolean
		{
			return complexIntersectionRectangle(target1, target2, accurracy).width != 0;
		}

		//返回两个任意形状的物体轮廓接触的矩形区域 
		public static function intersectionRectangle(target1:DisplayObject, target2:DisplayObject):Rectangle
		{
			// If either of the items don't have a reference to stage, then they are not in a display list 
			// or if a simple hitTestObject is false, they cannot be intersecting. 
			if (!target1.root || !target2.root || !target1.hitTestObject(target2))
			{
				return new Rectangle;
			}
			// Get the bounds of each DisplayObject. 
			var bounds1:Rectangle=target1.getBounds(target1.root);
			var bounds2:Rectangle=target2.getBounds(target2.root);
			// Determine test area boundaries. 
			var intersection:Rectangle=new Rectangle();
			intersection.x=Math.max(bounds1.x, bounds2.x);
			intersection.y=Math.max(bounds1.y, bounds2.y);
			intersection.width=Math.min((bounds1.x + bounds1.width) - intersection.x, (bounds2.x + bounds2.width) - intersection.x);
			intersection.height=Math.min((bounds1.y + bounds1.height) - intersection.y, (bounds2.y + bounds2.height) - intersection.y);
			return intersection;
		}

		//返回两个任意形状的物体实际象素接触的矩形区域 
		public static function complexIntersectionRectangle(target1:DisplayObject, target2:DisplayObject, accurracy:Number=1):Rectangle
		{
			if (accurracy <= 0)
			{
				throw new Error("ArgumentError: Error #5001: Invalid value for accurracy", 5001);
			}
			// If a simple hitTestObject is false, they cannot be intersecting. 
			if (!target1.hitTestObject(target2))
			{
				return new Rectangle;
			}
			var hitRectangle:Rectangle=intersectionRectangle(target1, target2);
			// If their boundaries are no interesecting, they cannot be intersecting. 
			if (hitRectangle.width * accurracy < 1 || hitRectangle.height * accurracy < 1)
			{
				return new Rectangle;
			}
			var bitmapData:BitmapData=new BitmapData(hitRectangle.width * accurracy, hitRectangle.height * accurracy, false, 0x000000);
			// Draw the first target. 
			bitmapData.draw(target1, HitTestUtil.getDrawMatrix(target1, hitRectangle, accurracy), new ColorTransform(1, 1, 1, 1, 255, -255, -255, 255));
			// Overlay the second target. 
			bitmapData.draw(target2, HitTestUtil.getDrawMatrix(target2, hitRectangle, accurracy), new ColorTransform(1, 1, 1, 1, 255, 255, 255, 255), BlendMode.DIFFERENCE);
			// Find the intersection. 
			var intersection:Rectangle=bitmapData.getColorBoundsRect(0xFFFFFFFF, 0xFF00FFFF);
			bitmapData.dispose();
			// Alter width and positions to compensate for accurracy 
			if (accurracy != 1)
			{
				intersection.x/=accurracy;
				intersection.y/=accurracy;
				intersection.width/=accurracy;
				intersection.height/=accurracy;
			}
			intersection.x+=hitRectangle.x;
			intersection.y+=hitRectangle.y;
			return intersection;
		}

		//矩阵 
		protected static function getDrawMatrix(target:DisplayObject, hitRectangle:Rectangle, accurracy:Number):Matrix
		{
			var localToGlobal:Point;
			var matrix:Matrix;
			var rootConcatenatedMatrix:Matrix=target.root.transform.concatenatedMatrix;
			localToGlobal=target.localToGlobal(new Point());
			matrix=target.transform.concatenatedMatrix;
			matrix.tx=localToGlobal.x - hitRectangle.x;
			matrix.ty=localToGlobal.y - hitRectangle.y;
			matrix.a=matrix.a / rootConcatenatedMatrix.a;
			matrix.d=matrix.d / rootConcatenatedMatrix.d;
			if (accurracy != 1)
			{
				matrix.scale(accurracy, accurracy);
			}
			return matrix;
		}
	}
}
